The present invention relates to a pressure relief apparatus, and more particularly, to a pressure relief apparatus for a high pressure slurry processing system.
In the processing of coal slurries, it has been found desirable to elevate a superheated slurry of about 50% water and about 50% particulate coal solids to pressures of 10,000-15,000 pounds per square inch (psi) and higher. Because of the presence of the particulate coal solids in the system, certain components of the system tend to become clogged, reducing or blocking slurry flow. To prevent the substantial damage which would result from the explosion of an over-pressurized reaction vessel, a rupture disc of conventional construction has been tested in an orifice open to a conduit of the processing system. It has been found, however, that the abrupt, high magnitude pressure drop resulting from the rupture of a rupture disc causes slurry flow within the system to be reduced drastically. Consequently, the particulate coal solids agglomerate, or set into a solid mass, thereby obstructing the reaction vessel of the system and associated slurry conduits. When a constant pressure pump is being utilized with the slurry processing system, an additional consequence is that the pump accelerates rapidly toward self-destructive velocities. As a third consequence, the slurry experiences a 500.degree.-700.degree. F. thermal shock that is potentially damaging to the pump, O-rings and other temperature-sensitive system components. Finally, upon rupture, the fragments of the rupture disc are propelled at a bullet-like velocity from the orifice, creating a life- and equipment-endangering situation.